NATATORES — ANATIDjE — MERGUS. 317 



white at base, then reddish, passing into brown ; tarsus uniform black. In the Collection of 

 H. C. De Rham is another, with more of a rufous tinge about the neck, and distinct brown 

 arrowheaded marks on the fore part and sides of the neck ; breast deep brown, with still 

 deeper brown bars ; beneath densely barred with brown ; tarsi apparently black, varied with 

 yellow. 



The difficulty of capturing these birds, and their consequent rarity for the purpose of 

 examination and comparison, has hitherto prevented us from being fully acquainted with their 

 history. It is not clear to me that the characters upon which specific distinctions have been 

 attempted to be founded among the birds of this genus are always to be relied on. Among 

 nine individuals now lying before me, belonging to two if not to three species, I do not 

 detect more than • 2 of an inch difference in the length of the tarsi. The length and per- 

 haps the shape of the central tail-feathers must vary with age. 



This species is not uncommon on our coast in winter. Mr. Audubon, however, states that 

 he has never seen this species along the shores of the United States, although some of the 

 genus go as far south in winter as the Gulf of Mexico. The Prince of Canino asserts of 

 another (L. buffoni, Boie ; L. parasiticus, Linnaeus), that it is only accidental in North 

 America ; so that possibly all the Gull-hawks or Yagers on the coast of the United States 

 may eventually be referred to one and the same species. 



FAMILY ANATIDM. 



Bill straight, stout, more or less depressed, covered with a thin membranous skin ; its edges 

 furnished with lamellar teeth, or with small denticulations ; the tip rounded and obtuse, 

 furnished with a nail. Wings moderate. Legs placed in or near the equilibrium. Feet 

 four-toed, palmated : hind toe free, placed high on the tarsus. Tibia almost entirely fea- 

 thered. Tail various, usually short, composed of from twelve to twenty feathers. Plumage 

 dense. * 



GENUS MERGUS. Linnaeus. 



Bill moderate, depressed, straight, slender, nearly cylindrical, tapering, armed at the tip with 

 a strong hooked nail ; the edges furnished with oblique acute teeth directed backwards. 

 Nostrils nearly medial, lateral, very small and pervious. Tarsi compressed. Hind toe 

 furnished with a broad membrane. Head crested. Tail short, rounded, of sixteen or 

 eighteen feathers. 



